Ship s log



(No Model.)

R. T. HALL.

SHIPS LOG.

No. 473,222. Patented Apr. 19.1892.

@cal @j/(Z NITED STATES PATENT OFFICE.

REYN OLD THOMAS-HALL, OF MERCHANTVILLE, NET JERSEY.

SHIPS LOG.

SPECIFICATION forming part of Letters Patent No. 473,222, dated April19, 1892.

Application filed September '7, 1891. Serial 110.405.040. (No model.)

To @ZZ 1,071,077@ t may concern.-

Be itknown that I, REYNOLD THOMAS HALL, passed assistant engineer in theUnited States Navy, (at present on board the United States flag-shi pPensacola, at anchor in the harbor of Valparaiso, Chile,) a citizen ofthe United States, residing atMerchantville',in the county of Camden andState of New Jersey, have invented a certain new and useful machine forapplying a principle in hydrostatics to the measurement of the speed ofvessels through the water; andI do hereby declare the following to be afull, clear, and exact description of myinvention, such as will enableothers skilled in the art to which it belongs to apply and use the same.

My invention relates to an improved automatic ships speedgage or shipslog utilizing a hydrostatic principle of motion of bodies in fluids,namely: Resistance to a plane from a fluid acting in a direction atright angles to its face is equal to the weight of a col- .umn of fluidthe base of which is equal in area to the plane and the altitude equalto that which is due to the velocity of the niotion or through which aheavy body-must fallto acquire that velocity, and resistance to a planemoving through a fluid is the same as the force of fluid in motion, withsame velocity on plane at rest. The resistance per square foot of areasustained by a wholly-submerged plane moving normally to itself throughseawater at a uniform speed of ten feet per second is one hundred andtwelve pounds, and for other speeds the resistances Vary as the squaresof the speeds. Thus, let V represent any velocity in feet per second andR the resistance per square foot due to that velocity; then, 102 is toV2 as is 112 to R. Conversely, by ascertaining the resistance to a planeunder the above circumstances the velocity per second and speed per hourmay be calculated. The velocity may be obtained mathematically, asfollows:

144 144 and R R 72; I l Y 1001i l .0077-77 V \/.007777 equa s e y infeet per second. Let K represent-speed (velocity) in knots per hour;then i K VXGSOXGOZLL and K 4 5\/ R I 2025 I- S03 i E? 5 R "ccnl-PVR 6'ELX that is, K equals 6.803 R; that is,-speed in knots per hour equals6.803 plus times the. square root of the resistance per square inch onthe submerged plane. 7o

The objects of my invention are, first, to provide an automaticgageg'second, to secure an accurate and correct knowledge of the shipsspeed through the Water; third, to provide for the indications beingread at any convenient place about the vessel remote from the spot wherethe gage is located; fourth, to measure the direct resistance per squareinch due to speed upon a vessels hull. I attain these objects by themechanism illustrated in 8o the accompanying drawings.

Figures I and 1l are the vertical sections of the gage; Fig. Ill, thehorizontal section of the same. Fig'IV shows the electric battery andgalvanometer in circuit. Fig.V shows a part of a vessel with myinventionattached in circuit Similarletters refer to similar parts i hroughoutthe several views.

The hatched portions in Figs. 1,11, and 9o III show the sections of thechamber, which is secured by its flanges A A A to a suitable form madefor the purpose, H, which is itself secured to the vessel.

In a recess in the front side of the chamber is secured the flexiblediaphragm B, to the inside of which is connected the lever necessary fortransmitting the motion of the liexible diaphram, and by which themovable pole C of an electric resistance-coil D is moved in such mannerthat the amount ot electric current passing through the resistance-coilD will be increased or decreased as the amount of pressure on thediaphragm B is increased or de creased.

Connected in circuit are the resistancecoils D, the electric battery E,and an electric indicating device or galvanometer F. Any pressure comingupon the diaphragm B will successively, through lever Y, crank S, leverX, and lever IV, come upon the movable pole C of the resistance-coil D,which in turn will increase or decrease the amount of current flowingthrough the electric circuit in which the resistance-coil D is located.

The variations in theamountof current are measured, as herein shown, bya galvanometer F, and the change in amount of current passing throughthe circuit at any instant will depend upon the dellection of thediaphragm B, which deflection is entirely dueto the resistance orpressure upon it.

I am aware that prior to my invention ships logs and speed-gages havebeen invented, depending upon the forward and aftward motion of theVessel through the Water, and therefore do not claim the utilization otthat principle, broadly; but

vWhat I do claim as my invention, and desire to secure by LettersPatent, is-

1. In a hydrostatic ships log, the combination, with a liexiblediaphragm below the water-line of the vessel and in direct contact withthe water, of a resistancecoil, its polepiece, connections between saidpole-piece and diaphragm, whereby movement ot thelatter causes avariation of resistance, an electric generator, and an indicating devicefor the Variations of resistance, the said generator, indicating device,coil, and pole-piece being in electric circuit,substantially as and forthe purpose described.

2. A hydrostatic ships log comprising a chamber having a exiblediaphragm therein below the Water-line of and at right angles to thecourse of the vessel, the outer side of said diaphragm being acted upondirectly by the water, a resistance, its movable pole-piece,an electricgenerator, and an indicating device in electric circuit with saidpole-piece and resistance, and connections between said polepiece anddiaphragm, whereby movement ot the diaphragm is communicated to the polepiece, substantially as and for the purpose described.

In a ships log, the combination, with a iiexible diaphragm inA contactwith the water below the water-1ine of the vessel, of a resistance coilhaving a series of contacts, a partially-rotatable pole-piece adapted tomove over said contacts, connections between said pole-piece anddiaphragm to move the former, an electric generator, 'and a galvanometerin circuit with said generator, resistance-coil, and pole-piece,substantially as described.

REYNOLD THOMAS HALL.

YVitnesses:

OLIVER L. HALL, Eo. H. BARBER.

